Avalanche Advisory

ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.

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The Bottom Line

Today a MODERATE avalanche danger exists in the Alpine and at Treeline. Triggering an isolated wind slab 6”-20” thick is possible on steep wind-loaded features. In places protected from the wind loose snow avalanches could be fast moving and easily knock you off your feet in the wrong place. Identify wind-loaded features, turn around if you see shooting cracks, and be conservative near high consequence terrain. Also avoid slopes with glide cracks and give cornices a wide berth today - both of these hazards are unpredictable.

A LOW avalanche danger exists below 1000’ where triggering an avalanche is unlikely.

If you are thinking of going to Summit Lake, be aware that different avalanche hazards exist within the snowpack. Click HERE to read the Summit Lake Summary from this last weekend.

Show the Complete North American Avalanche Danger Scale

North American Public Avalanche Danger Scale

Avalanche danger is determined by the likelihood, size and distribution of avalanches.

Danger Level

Travel Advice

Likelihood of Avalanches

Avalanche Size and Distribution

5 Extreme

Avoid all avalanche terrain.

Natural and human- triggered avalanches certain.

Large to very large avalanches in many areas.

4 High

Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

Natural avalanches likely; human- triggered avalanches very likely.

Large avalanches in many areas; or very large avalanches in specific areas.

She Jumps in collaboration with the Alaska Avalanche School & CNFAIC will be putting on a basic avalanche rescue clinic focused on companion rescue. Sorry guys, this is a women's specific clinic and will review efficient search techniques using a beacon, probe and strategic shoveling. This is a great opportunity to get some hands on practice with the help of an instructor. For more details click HERE.

Avalanche Problem 1

Wind slabs: Over the last few days several wind events combined with over a foot of new snow have created fresh wind slabs up to 20” thick on leeward features. The good news is this new snow is bonding well with the old snow below, however not enough time has passed for this hazard to have completely healed. Wind slabs are likely to be tender and found on slopes steeper than 38°. Trigging an isolated wind slab in the wrong place, like over a cliff or above a terrain trap, could have high consequences. Should today’s visibility allow for easy access into steeper terrain avoid wind-loaded features, watch for shooting cracks, and choose your terrain wisely.

Cornices: Already large cornices have received additional stress over the last 3 days. Strong winds have been adding weight to their robust size and could be extra tender today. These backcountry bombs have a tendency to break farther back than expected and can send you for an undesirable ride. Approach ridgelines with caution and avoid being on or directly below cornices features.

Yesterday's poor visibility prevented a view into the alpine, but here's a photo from Tuesday, Jan.19th, of Tincan Proper. Note the large cornice near the ridge and wind-loaded pillow features. Above photo by Aleph J-Bloom

In places protected by the wind 12” of loose unconsolidated snow could be fast moving in steep terrain. Loose snow can easily knock a person off of their feet or take them for a ride over a cliff or into a terrain trap. Manage your ‘sluff’ by letting loose snow move past you and avoid terrain features with high consequences.

Additional Concern

Today at Treeline (the 1,000’ – 2,500’ elevation band) on all aspects, pay attention to and avoid glide cracks. These can lead to glide avalanches that are very unpredictable as we have seen over the past few days. There is no discernable pattern to predict a failure as they tend to fail naturally and on their own schedule. Warm temperatures can trigger them and so can cooling temperatures. Cracks can form and release in seconds or days later or sometimes a glide crack won’t release at all. The new snow has made it harder to see the existing cracks and glide releases in the terrain.

It is best to give glide cracks a wide berth. Avoid spending time underneath and if skiing or riding in terrain with glide cracks, try and map them out before your travels so as not to end up directly on top of or inside one. Remember, when these do fail, they tend to be destructive, failing to the ground and bringing the entirety of the snowpack with them.

Close up comparision of a glide crack on the East face of Seattle Ridge that released suddenly on Jan.16. These glide releases are now covered with fresh snow and harder to see.

Mountain Weather

Yesterday 5” of new snow was recorded at Center Ridge weather station. Temperatures increased into the low 30’s F at 1000’ causing wet heavy snow to fall along the road. Ridgetop winds were light from the Northeast.

Overnight precipitation stopped and temperatures cooled into the high 20’s.

Today expect valley fog in the morning. Skies are expected to be mostly cloudy. There’s a chance of light snowfall by early afternoon. Expect temperatures to increase into the low 30’s F and wind to be light from the Northeast.

PRECIPITATION 24-hour data (6am - 6am)

Temp Avg (F)

Snow (in)

Water (in)

Snow Depth (in)

Center Ridge (1880')

30

5

0.5

88

Summit Lake (1400')

31

0

0

27

Alyeska Mid (1700')

n/a

n/a

n/a

n/a

RIDGETOP 24-hour data (6am - 6am)

Temp Avg (F)

Wind Dir

Wind Avg (mph)

Wind Gust (mph)

Sunburst (3812')

25

NE

14

44

Seattle Ridge(2400')

26

n/a

n/a

n/a

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Dec 18, 2018 )

AREA

STATUS

WEATHER AND RIDING CONDITIONS

Glacier District

Johnson Pass:

Open

Please stay on trail to avoid resource damage through Forested areas.

Placer River:

Closed

Closed

Skookum Drainage:

Closed

Closed

Turnagain Pass:

Closed

Closed November 21 due to inadequate snow conditions. #hopeforsnow

Twentymile:

Closed

Closed

Seward District

Carter Lake:

Open

Lost Lake Trail:

Open

Please stay on trail to avoid resource damage through Forested areas.

Primrose Trail:

Open

Please stay on trail to avoid resource damage through Forested areas.

Resurrection Pass Trail:

Closed

Closed for the 2018/19 season. Next season will be open to motorized use.

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.
This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.